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Mariano Carmona Gallardo
Grupo de Física Nuclear ExperimentalInstituto de Estructura de la Materia
CSIC-Madrid
O. Tengblad1, B.S. Nara Singh2, M. Hass3 , M. Alcorta1, M.J.G. Borge1, J.A. Briz1, M.Cubero1, C. Cruz1, R. Dominguez-Reyes1, B. Fulton2, H. Fynbo5, N. Gordillo6, G. Haquin4 , Y. Nir-El4, V. Kumar3, A. Maira6, A. Muñoz6, A. Perea1,Z. Yungreis4
1Intituto de Estructura de la Materia-CSIC, Madrid, Spain2University of York, York, UK3Weizmann Institute of Science, Rehovot, Israel4Soreq Research Center, Yavne, Israel5Aarhus University, Aarhus, Denmark6Centro de Microanálisis de Materiales-UAM, Madrid, Spain
WORKSHOP ON REACTIONS OF ASTROPHYSICAL
INTEREST (EUROGENESIS )
April 2011
ASTROPHYSICAL FACTOR OF 3He(4He,γ)7Be USING ACTIVATION METHOD
OUTLINE
M. Carmona-Gallardo MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
1. MOTIVATION FOR 3He(4He,γ)7Be EXPERIMENT
2. EXPERIMENTAL MEASUREMENT OF(E) FOR 3He(4He,γ)7Be
3. CMAM FACILITY
4. SET-UP
5. EXPERIMENTAL MEASUREMENTS: CONSIDERATIONS & ESTIMATIONS
6. OBSERVABLES MEASUREMENTS
7. RESULTS
8. ONGOING AND FUTURE WORK
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
MOTIVATION
M. Carmona-Gallardo MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
S34(0)= 0.56 ± 0.02 (exp) ± 0.02 (model) keV·b compared with the previous value (0.53 ± 0.05) keV·b
(The analysis is based on all activation data plus ERNA recoil data)
Solar fusion cross sections II: arXiv:1004.2318v3
1. Direct detection of 7Be recoils produced during the reaction. (European Recoil Separator for Nuclear Astrophysics)
2. Detection of direct gamma reaction produced during the reaction: DC 429 keV, 429 keV 0
3. Detection of gamma radiation of 478 kev from de-excitation of 7Li after decay of 7Be:
T1/2=53.350 (50) days.
EXPERIMENTAL MEASUREMENT OF(E) FOR 4He(3He,)7Be
e+
7Be7Li
Proton
Neutron
4He
3He
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be M. Carmona-Gallardo
Activation MethodDirect detection of 7Be or prompt radiation detection
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
GAS TARGET OF 4He AND BEAM OF 3He+ PARTICLE
BEAM ENERGIES: 2.3, 3.2, 4, 4.4, 4.8 5.3 MeV
THE GAS CHAMBER MUST BE ELECTRICALLY INSULATED FROM THE LINE, SEPARATED BY A OIL
FOIL MUST KEEP THE PRESSURE DIFFERENCES BETWEEN LINE AND CHAMBER
AS THIN SCATTERING-FOIL AS POSSIBLE WHILE STILL RESISTANT TO HEAT FROM THE BEAM NI FOIL 1 m THICK
GAS SYSTEM TO GUARANTEE CONSTANT PRESSURE IN THE REACTION CHAMBER
EXPRESION :
·4d
targetin the particles ofNumber tN
particleincident ofNumber pN
dd
dtNpN produced Be7
lab
lab
lab
M. Carmona-Gallardo
EXPERIMENTAL MEASUREMENT OFs(E) FOR 4He(3He,)7Be II
OBSERVABLES: Nº ion 7Be, nº of incident 3He+ ion, nº ions 4He in the target
EXPERIMENT IN NOVEMBER 2009
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
M. Carmona-Gallardo
CMAM
• Centro de Microanálisis de Materiales de Madrid (CMAM), at Universidad Autónoma de Madrid
•Seven experimental lines. One line for Experimental Nuclear Physics operated by Grupo de Fisica Nuclear Experimental del IEM-CSIC
•High voltage system Cockcroft-Walton
•Tandem electrostatic accelerator of 5MV
•Two ion sources: Sputtering source
Duoplasmatron source(used during the experiment)
NUCLEAR PHYSICS LINE
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
EXPERIMENTAL SET-UP
Silicon detector
Collimator
Pressure gauge
4He Gas
Cu catcherNi foil
-180 V suppressor
3He beam
Scattered beam
Insulator
Np (CHARGE INTEGRATION)
Np (MONITORING)
Nt=9.966 ·1018· l·P/(T+T0)7Be recoils
dΩlab
dΩ
dσt
Np
N )(º 7
BeN
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be M. Carmona-Gallardo
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
EXPERIMENTAL SET UP II
M. Carmona-Gallardo MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
M. Carmona-Gallardo Astrophysical Factor of 3He(4He,γ)7Be MADRID April 2011
Catcher electrically connected to the chamber
Suppressor at -100V to avoid escape of e- and loss of current integrations
SRIM and LISE++ used for previous calculations-.
≈1µA (6.2 · 1012 3He/s) ≈3µbar ≈50torr & 300 K
3He(4He,γ)7Be Eγ =429 KeV
· θ ≈ 45º ·Ebeam ≈ 4 MeV / I ≈ 1µA ·tNi ≈ 1 µm / d = 8.9 g/cm3
·Energy-loss in the Ni foil taken into account. Assuming the R.S at the middle of the foil
Ebeam= 4 MeV 26.04 cm Ni foil - Si Energy Loss in Ni foil
θ/2)(sen
1
42E
eZZ
4
1
d
d4
2
0
221
7Be in catcher
Particles mesaured at Si detector same than RS
-100V
C.R.≈ 295 7Be/s
≈4155 3He at 45º
E(3He at Si) ≈ 2.694 MeV
EXPERIMENTAL MEASUREMENTS:CONSIDERATIONS &ESTIMATIONS
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
Previous and post calibration of Silicon detector with triple alpha and 148Gd sources
Some Parameters: Bias (detector de Si): -100 V Leakage current: 0.48 µA Leak Rate 0.10 torr/h (Very good) Line pressure ≈ 1.1 · 10-6 torr Typical currents 180 - 200 nA
Six catchers with different parameters
MAESTRO: Number of particles which suffer elastic scattering Beam Intensity Energy of Particles Beam energy
C foil used to measure the detector angle precisely. (Z(C) < Z(Ni))
Ni foil thickness measured with an external set up in a vacuum chamber and a Si detector
)1(
cos21
E
E2
2
beam
Si
CM
M. Carmona-Gallardo Astrophysical Factor of 3He(4He,γ)7Be MADRID April 2011
EXPERIMENTAL MEASUREMENTS:CONSIDERATIONS &ESTIMATIONS
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
27
4 HeNibCM
EEEE
OBSERVABLES MEASUREMENTS
M. Carmona-Gallardo
A) ECM
We assume the reactions take placed at the center of gas target [1][2]
Beam energies with ±20 keV error
Energy loss in the Ni foil and gas target simulated with TRIM
Straggling in Ni foil and Gas target simulated with TRIM negligible•[1] B. S. Nara Singh et al. PRL 93, 262503 (2004)•[2]A.R. Junghans et al. PRL 88, 0411101 (2002)
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OBSERVABLES MEASUREMENTS
M. Carmona-Gallardo
B) 4He: (Nt : number of gas target ions per cm2 ) Assuming ideal gas due to the low pressures we can consider:
Ct TT
PlN
0
1810·66.9
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
P: gas pressure (Torr)T0 : room temperature (k)l: target length (cm)
Tc temperature correction due to the beam heating measured experimentally using the 1.518 MeV resonance in the 10B(,p)13C. 17K for 500nA @ 2 MeV. [1]
Ebeam (MeV) Pon (Torr) T (K) DISTANCE (catcher-foil)
2.3 54.68±0.21 300.2633 13.95±0.01
3.2 63.77±0.27 309.2261 13.95±0.01
4 50.64±0.02 313.7672 11.63±0.01
4.4 50.66±0.01 316.5130 11.48±0.01
4.8 50.83±0.07 318.4352 11.58±0.01
5.3 56.68±0.29 319.0396 13.95±0.01
[1] B. S. Nara Singh et al. PRL 93, 262503 (2004)
OBSERVABLES MEASUREMENTS
M. Carmona-Gallardo
C) 3He: Charge Integration & Elastic Scattering in the Ni foil
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
Ebeam (MeV)
INTENSITY (pulses)
NP(charge integration)
(at)
Rutherford spectra
integration
NP(3He with R.s
2.3 4.54E+7 2.834E+16 5.90E+07 2.79E+16
3.2 8.00E+7 4.993E+16 4.93E+07 5.00E+16
4 1.00E+8 7.321E+16 4.33E+07 7.17E+16
4.4 8.37E+7 5.226E+16 2.54E+07 5.16E+16
4.8 5.16E+7 3.224E+16 1.29E+07 3.17E+16
5.3 6.24E+7 3.893E+16 1.27E+07 3.85E+16
M. Carmona-Gallardo
D) 7Be:
E) Complementary measurements
Angle of Silicon DetectorNi foil thickness
OBSERVABLES MEASUREMENTS
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
~900 cts. After 6 days
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
M. Carmona-Gallardo
RESULTS
ECM
(KeV)b
)S34(E) (keV·b)
(INTEGRATION)S34(E) (keV·b)
(RUTHERFORD)
903.631 1,872 0.398 0.407
1487.45 2,896 0.304 0.303
2010.64 3,78 0.295 0.304
2256.03 5,075 0.363 0.370
2499.05 5,502 0.367 0.376
2791.21 6,446 0.402 0.410
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
GOOD AGREEMENT
BETWEEN BOTH TECHNIQUES
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
M. Carmona-Gallardo
RESULTS COMPARATION WITH PREVIOUS MEASURMENTS
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK
M. Carmona-Gallardo
ONGOING & FURTURE WORK
Try to reduce statistical errors with new activation method measurements
New strategy as we only have one low HpGe station
Calculate all errors
Use different theoretical model in order to extrapolate up to S34(0)
MADRID April 2011Astrophysical Factor of 3He(4He,γ)7Be
OUTLINE
MOTIVATION
MEASUREMENT OF (E)
CMAM
SET UP
CONSIDERATIONS & ESTIMATIONS
OBSERVABLES
RESULTS
ONGOING AND FUTURE WORK